Electrode assembly with hybrid weld

ABSTRACT

An electric storage battery including a jelly roll type electrode assembly having a mandrel. The mandrel includes a positive portion, negative portion and removable portion. The mandrel has two faces with grooves dimensioned to accommodate positive and negative feedthrough pins. Electrodes are welded to the mandrel using an ultrasonic weld to the face on which the electrodes are attached. An additional weld is made to at least one ultrasonic weld using a through-mandrel laser weld, incident on the opposite face from which the ultrasonic weld. The laser melts the mandrel such that molten mandrel material fills the area under the foil at the area of the ultrasonic weld, the surface area of the foil being significantly increased by knurls formed by ultrasonic welding. Electrodes are wrapped around the mandrel using the removable portion to wind the mandrel. The mandrel allows tighter wrapping of the jelly roll assembly increasing battery miniaturization.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

FIELD OF THE INVENTION

The invention relates to a jelly roll-type electric battery assemblyhaving an integrated mandrel with a hybrid electrode weld allowing forincreased compactness and to a method of manufacture.

BACKGROUND OF THE INVENTION

Batteries for medical devices have demanding requirements. They shouldbe small, have a long life, high power output, low self-discharge rate,compact size and high reliability. The need for miniaturization whilemaintaining or increasing output means that as much of the batteryfootprint as possible should be used for power storage resulting in theconcomitant elimination of dead space. However, while the elimination ofdead space should result in greater miniaturization, it also results ina greater difficulty of assembly due to the increasingly small size ofthe component parts.

Traditionally, jelly roll type batteries have been made by using amandrel to wrap electrodes around. Once wrapped, the mandrel is removedproviding a jelly roll wrapped electrode assembly for use in a battery.However, removal of the mandrel from the core of the jelly rollinherently presents the potential of damaging the jelly roll due to thepossibility of pulling the core of the jelly roll out with the mandrel.Therefore, the jelly roll should not be wrapped tight to avoid thisproblem. Conversely, a loosely wrapped jelly roll wastes space anddecreases battery capacity and power due to size constraints. Morerecently, jelly roll storage batteries have been made using arod-shaped, non-conductive, non-deformable core around which electrodesare wrapped. Conductive tabs are added to each electrode to complete thecircuit.

U.S. Pat. No. 7,442,465 to Kim et al., discloses a rechargeable batterywhich has a non-deformation core. Once the positive and negativeelectrodes are wound around the core, conductive tabs are attached tothe electrodes and the core serves to prevent deformation of the jellyroll, but does not conduct current.

U.S. Provisional Patent Application No. 60/348,665 to Nakahara et al.describes a feedthrough pin that is directly connected to an inner endof an electrode. The pin extends from the jelly roll and through thebattery case and functions as a battery terminal. The feedthrough pinfits into a slotted ‘C’-shaped mandrel. The positive electrode isconductively connected to the pin which fits within the ‘C’-shapedmandrel. As the positive electrode is wound, a separator is insertedbetween the feedthrough pin/mandrel and the positive electrode. Anegative electrode is inserted between the separator and thepin/mandrel. The separator and negative electrode are held in the jellyroll by the tension created between the feedthrough pin/mandrel and thepositive electrode. After winding, a metal tab is welded to the negativeelectrode and the tab contacts the battery case endcap to complete thecircuit.

Both of the aforementioned batteries require the placement of at leastone tab on an electrode to complete the circuit during or after windingthe electrodes. In either case, the passive connection of one of theelectrodes to the case is required for the circuit to be completed.

Therefore, a need exists for an improved electrode assembly.

SUMMARY OF THE INVENTION

Therefore, in various embodiments, the invention provides an electricstorage battery including a jelly roll type electrode assembly having anintegrated mandrel is provided. The mandrel includes a positive portion,negative portion and removable portion. The mandrel has two faces withgrooves dimensioned to accommodate positive and negative feedthroughpins. Electrodes are welded to the mandrel using an ultrasonic weld tothe face on which the electrodes are attached. An additional weld ismade to at least one ultrasonic weld using a through-mandrel laser weld,incident on the opposite face from which the ultrasonic weld. The lasermelts the mandrel such that molten mandrel material fills the area underthe foil at the area of the ultrasonic weld, the surface area of thefoil being significantly increased by imprints of knurls formed byultrasonic welding. One result is the molten mandrel material alsomelting the foil which has a lower melting temperature allowing a mixingof the two materials. The electrodes are wrapped around the mandrelusing the removable portion to wind the mandrel. The mandrel allowstighter wrapping of the jelly roll assembly increasing batteryminiaturization.

Therefore, in various exemplary embodiments the invention includes, anelectrode assembly comprising a mandrel having a first face and a secondface, comprising a positive portion, a negative portion and one or moreremovable portions; a positive electrode; a negative electrode; apositive feedthrough pin; and a negative feedthrough pin; wherein thepositive portion and the negative portion are connected by one or moreremovable portions; wherein the positive feedthrough pin is conductivelyconnected to the positive portion and the negative feedthrough pin isconductively connected to the negative portion; wherein the positiveelectrode is attached to the positive portion and the negative electrodeis attached to the negative portion; wherein one or both electrodes areconductively connected to the mandrel by an ultrasonic weld from thesame face of the mandrel to which the one or both electrodes areattached; and wherein one or both electrodes are conductively connectedto the mandrel by a laser weld from the opposite face of the mandrelfrom which the one or both electrodes are attached.

In some embodiments according to the invention the ultrasonic weldresults in one or more knurls on the surface of the electrode in contactwith the mandrel. In various embodiments the laser weld is formed aboutthe one or more knurls. In some embodiments, the positive portion and/orthe negative portion have a groove configured to accept the feedthroughpins. In these embodiments, the positive and negative feedthrough pinsare independently selected from steel, platinum, aluminum, titanium,vanadium, niobium, molybdenum, platinum-iridium, and copper and theiralloys.

In still other exemplary embodiments the invention provides a method ofpreparing an electrode assembly comprising: providing a mandrel having afirst face and a second face and comprising a positive portion and anegative portion connected by one or more removable portions; providinga positive electrode; providing a negative electrode; providing apositive feedthrough pin; providing a negative feedthrough pin;conductively connecting the positive feedthrough pin to the positiveportion and the negative feedthrough pin to the negative portion;attaching the positive electrode to a face of the positive portion byultrasonic welding from the same face of the mandrel to which theelectrode is attached; attaching the negative electrode to a face of thenegative portion by ultrasonic welding from the same face of the mandrelto which the electrode is attached; attaching the positive electrode toa face of the positive portion by laser welding from the opposite faceof the mandrel to which the electrode is attached; and attaching thenegative electrode to a face of the negative portion by laser weldingfrom the opposite face of the mandrel to which the electrode isattached.

In these embodiments of the invention, the ultrasonic welding providesone or more knurls. In some embodiments, the laser welding providesmolten mandrel material about the one or more knurls. In variousembodiments of the invention, the method of making the electrodeassembly includes providing a groove configured to accept the positivefeedthrough pin on the positive portion on a face of the mandrel. Inthese embodiments, the positive feedthrough pin is conductivelyconnected in the groove on the positive portion. In various embodiments,the method according to the invention also provides providing a grooveconfigured to accept the negative feedthrough pin on the negativeportion on a face of the mandrel. In these embodiments, the negativefeedthrough pin is conductively connected in the groove on the negativeportion.

These and other features and advantages of the present invention will beset forth or will become more fully apparent in the description thatfollows and in the appended claims. The features and advantages may berealized and obtained by means of the instruments and combinationsparticularly pointed out in the appended claims. Furthermore, thefeatures and advantages of the invention may be learned by the practiceof the invention or will be apparent from the description, as set forthhereinafter.

BRIEF DESCRIPTION OF THE FIGURES

Various exemplary embodiments of the compositions and methods accordingto the invention will be described in detail, with reference to thefollowing figures wherein:

FIG. 1 is a schematic diagram of one embodiment of an electrode assemblymade using a mandrel according to the invention. In this embodiment, thefeedthrough pins are on the same side face of the mandrel;

FIGS. 2A and 2B illustrate a mandrel according to the embodiment of theinvention illustrated in FIG. 1. FIG. 2A is a side-plan view of themandrel. FIG. 2B is a top-plan view of the mandrel of FIG. 2A;

FIG. 3 is a schematic diagram of an electrode assembly made usinganother embodiment of the mandrel according to the invention. In thisembodiment, the feed through pins are on opposite faces of the mandrel;

FIG. 4 is a schematic diagram of the mandrel illustrated in FIG. 1 withelectrodes attached to the positive portion and the negative portion ofthe mandrel;

FIG. 5 is a schematic diagram of the mandrel shown in FIG. 4 withpositive and negative feedthrough pins attached and a battery cap andinsulator;

FIG. 6 illustrates the embodiment of a completed electrode assemblyusing the mandrel shown in FIG. 4 and with two separators attached. Theview shown in FIG. 6 is from the opposite face as the view from FIG. 5;

FIGS. 7A, 7B, 7C and 7D are schematic, top-plan views of four jelly rollelectrode assemblies using different mandrels to make an interconnectjoint according to the invention;

FIGS. 8A and 8B show a battery made using the coiled electrode assemblymade using a mandrel according to the invention. FIG. 8A shows theelectrode assembly in the battery case before the removable portion isdetached. FIG. 8B shows the completed battery with the removable portiondetached and the electrode assembly ready to be sealed in the batterycase;

FIG. 9 is a schematic diagram of another embodiment of the mandrelaccording to the invention having two separate positive and negativeportions, each with its own removable portion;

FIGS. 10A and 10B illustrate a separate embodiment of a mandrel usefulin making an interconnect according to the invention. This embodiment ofthe interconnect joint uses a mandrel having a separate stud pin forconductively connecting the positive and negative electrodes. FIG. 10Ais a side-plan view showing a mandrel with the location for a grooveincluding a welding site for a stud pin used to complete the connectionbetween the mandrel and the positive and negative electrode pins. FIG.10B is a top-plan view of the mandrel shown in FIG. 10A;

FIGS. 11A and 11B illustrate another embodiment of a mandrel useful inmaking an interconnect according to the invention. FIG. 11A is aside-plan view of the mandrel according to the invention and FIG. 11B isa top-plan view of the same mandrel. This embodiment of the interconnectjoint uses a mandrel having separate grooves for stud pins forconductively connecting the positive and negative electrodes;

FIG. 12 is a side-plan view of a partially assembled electrode assemblyaccording to one embodiment of the invention using the mandrel shown inFIGS. 10A and 10B;

FIG. 13 is a side-plan view of a separate embodiment of an interconnectjoint according to the invention. In this embodiment, the mandrel iswelded to the feedthrough pins by a laser weld incident on the oppositeface of the from that on which the feed through pin is fixed. In theembodiment of the mandrel shown the feedthrough pins are on oppositefaces of the mandrel;

FIG. 14 is a schematic representation of a side-plan view of a hybridweld used to attach one or both electrodes to the mandrel. In this view,an ultrasonic weld is used to attach the electrodes to opposite faces ofthe mandrel, this creates imprints of knurls or deformations on theelectrode/mandrel interface. A laser weld, incident from the oppositeface of the mandrel than the ultrasonic weld is then used to reinforcethe ultrasonic weld assuring the connection;

FIG. 15 is a micrograph of a laser weld with laser incident on theopposite face of the mandrel. Bar is 1⁻² inch (0.25 mm).

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In General

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an” and “the” include plural reference unless thecontext clearly dictates otherwise. As well, the terms “a” (or “an”),“one or more” and “at least one” can be used interchangeably herein. Itis also to be noted that the terms “comprising”, “including”,“characterized by” and “having” can be used interchangeably.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs. All publications and patentsspecifically mentioned herein are incorporated by reference for allpurposes including describing and disclosing the chemicals, instruments,statistical analyses and methodologies which are reported in thepublications which might be used in connection with the invention. Allreferences cited in this specification are to be taken as indicative ofthe level of skill in the art. Nothing herein is to be construed as anadmission that the invention is not entitled to antedate such disclosureby virtue of prior invention.

As used herein, the term “mandrel” means an interior core at least aportion of which can be an integral part of the electrode assembly. Theterm “interconnect joint” refers to a conductive connection between theelectrical components of a battery including a mandrel. While themandrel may, itself not be conductive, those parts of the electrodeassembly required for an electric current, including, at least, positiveand negative electrodes and positive and negative feedthrough pins areconductively connected on the mandrel. In addition, the term “electrode”is used to refer to an electrode substrate that can be coated with anactive material. The electrode can include a current collectingsubstrate in the form of multiple “plates” or panels conductivelyconnected to each other. Alternatively, the electrode comprises asubstrate in the form of a strip of thin conductive material such as afoil. When the electrode is formed using a foil or thin conductive stripas a substrate, the electrode can be considered an “electrode strip”.

As used herein the terms “heat sealed” and “heat sealer” refer toconventional methods known in the art in which a machine applies heat toseal a material such as a thermoplastic material. Of the several typesof heat sealers, one is a continuous heat sealer that applies acontinuous heat. A continuous heat device or sealer can be constructedusing a cartridge heater that is inserted into an appropriate sizeopening in a block, such as metal or ceramic, having a predeterminedshape and desirable thermal properties. A second type of heat sealer isan impulse heat sealer. Generally, an impulse heat sealer uses astationary element (such as a nichrome wire) that is heated by passing acurrent through it for a period of time.

The invention and the various features and advantageous details thereofare explained more fully with reference to the non-limiting embodimentsthat are illustrated in the accompanying drawings and detailed in thefollowing description. Descriptions of well known components andprocessing techniques are omitted so as not to unnecessarily obscure theinvention in detail but such descriptions are, nonetheless, included inthe disclosure by incorporation by reference of the citations discussed.It should be understood, however, that the detailed description and thespecific examples, while indicating preferred embodiments of theinvention, are given by way of illustration only and not by way oflimitation. Various substitutions, modifications, additions and/orrearrangements within the spirit and/or scope of the underlyinginventive concept will become apparent to those skilled in the art fromthis detailed description.

The Invention

The present invention provides a mandrel useful in making a jelly rollelectrode assembly and an electric storage battery. The mandrel includesa positive portion, a negative portion and one or more removableportions adjacent to the positive and/or negative portion(s). A passageis provided between the positive and negative portions. The mandrel canbe planar having two faces with a groove on each of the positive andnegative portions. The grooves can be on the same or opposite faces ofthe mandrel. The grooves are dimensioned to accommodate positive andnegative feedthrough pins.

The positive and negative electrodes and the positive and negativefeedthrough pins can be conductively connected to the mandrel when usedto make an electrode assembly. One or more separators can be used toinsulate the electrodes. For example, a separator can be passed throughthe passage of the mandrel so as to be juxtaposed alongside both thepositive and negative electrodes. The removable portion(s) can be usedas a handle to rotate mandrel, electrodes and one or more separators.Rotation of the mandrel wraps the electrodes and one or more separatorsaround the mandrel to provide a jelly roll electrode assembly. The jellyroll assembly can be secured by heat sealing one or more protruding endsof the one or more separators with heat.

Referring now to FIG. 1, one embodiment of an electrode assemblyaccording to the invention is illustrated. FIG. I illustrates anelectrode assembly 16 including a conductive mandrel 20 having apositive portion (obscured by separator 51) and a negative portion 24,positive and negative electrodes 30 and 32 and positive and negativefeedthrough pins 42 and 44. Mandrel 20 further includes removableportion 26 and a breakaway notch 28. As illustrated, positive electrode30 and negative electrode 32 can be conductively connected to theconductive mandrel 20 on opposite faces while feedthrough pins 42 and 44can be conductively connected in place on the same face of the mandrelthereby creating the interconnect joint. In the embodiment shown,positive electrode 30 and the negative electrode 32 can be conductivelyconnected by welding electrodes 30 and 32 to a flat surface of themandrel 20. In this embodiment, a single separator 51 can be interwovenbetween positive and negative portions 22 and 24 of mandrel 20 throughpassage “p” to provide electrode assembly 16.

It should be appreciated that the mandrel can be formed of anyconductive material. For example, the mandrel can be formed of stainlesssteel or aluminum. Alternatively, the mandrel can be made from puretitanium or titanium alloy such as grade 5 or grade 23, nickel, copper,vanadium, their alloys and combinations thereof.

While the mandrel can be made using any appropriate process, in oneaspect the mandrel can be made using electric discharge machining (EDM).Alternatively, the mandrel can be made by metal extrusion or byinjection molding depending on the needs of the battery and thecomposition of the mandrel. The grooves for the feedthrough pins can bemade in the mandrel by machining, etching, or other suitable methods toprovide a groove.

The width of mandrel 20 can be from about 0.2 to about 0.5 inches, moreparticularly from about 0.25 to about 0.4 inches and most particularlyfrom about 0.3 to about 0.35 inches. Generally, the length of themandrel ranges from about 0.5 inches to about 1 inch, more particularlyfrom about 0.6 to about 0.8 inches and most particularly from about 0.7to about 0.75 inches. The thickness of the mandrel ranges from about0.01 to about 0.05 inches, more particularly from about 0.015 inches toabout 0.03 inches and most particularly from about 0.02 to about 0.027inches.

Electrodes 30 and 32 can vary in size, shape and length. Generally theelectrode can be a foil or other thin malleable conductive substrate. Invarious embodiments, the foil can be in the form of a metal foil suchas, for example, aluminum, steel, silver, copper, nickel, titanium,vanadium, and alloys thereof. The length of the electrodes can rangefrom about 2 inches to about 20 inches, particularly from about 4 inchesto about 18 inches and most particularly from about 6 inches to about 16inches. The width of the electrodes can range from about 0.1 to about 2inches, more particularly from about 0.2 to about 1.75 inches and mostparticularly from about 0.3 to about 1.5 inches. The thickness of theelectrodes can vary from about 0.003 inches to about 0.04 inches, inparticular from about 0.004 to about 0.03 inches and most particularlyfrom about 0.005 to about 0.025 inches.

The electrodes can vary in composition depending on the batterychemistry being used and the mandrel can be optimized for such.

Suitable separator material can be any non-conductive material such aspolyethylene, polypropylene and layered combinations thereof. Theseparator generally has a larger width and length than the electrode(s)it covers so as to fully encase the electrode(s). Suitable separatorshave a length of from about 4 inches to about 36 inches, in particularfrom about 8 inches to about 34 inches and most particularly from about12 inches to about 30 inches and widths of from about 0.2 inches toabout 2 inches, in particular from about 0.3 inches to about 1.75 inchesand most particularly from about 0.4 inches to about 1.5 inches.Suitable thicknesses for separators range from about 0.0008 inches toabout 0.004 inches. Generally, separator 51 can be sized appropriatelyto extend beyond the bottom portion of positive and negative portions 30and 32 after removal of removable portion 26.

Feedthrough pins can be sized to fit within the grooves and can be madeof any electrically conductive material. For example, feedthrough pins42 and 44 can be made of steel, platinum, aluminum and titanium,vanadium, and alloys thereof. In some embodiments, the feedthrough pinscan be made of an alloy such as, for example, platinum-iridium such as90Pt/10Ir. The length of the positive and negative feedthrough pins canrange from about 0.4 to about 1 inches in length, more particularly fromabout 0.5 to about 0.75 inches and most particularly from about 0.5 toabout 0.7 inches. The diameter of the feedthrough pins can vary and canbe from about 0.005 to about 0.3 inches, in particular from about 0.01to about 0.025 inches and most particularly from about 0.01 to about0.015 inches. The feedthrough pins extend outside of the battery caseand can be cut to length as required.

The phrase “removable portion” refers to a portion of the mandrel thatcan be detached from the remainder of the mandrel. This can beaccomplished by scoring a groove deep enough to allow the portion to be“snapped off” from the remainder of the mandrel. Alternatively, theremoval portion can be detached by cutting, breaking, tearing orclipping the portion from the remainder of the mandrel.

FIGS. 2A and 2B illustrate a mandrel according to the exemplaryembodiment of the invention illustrated in FIG. 1. The mandrel 20 isplanar having two faces. The mandrel 20 has a positive portion 22 and anegative portion 24 with “p” separating the two portions. In addition,the mandrel 20 also has a removable portion 26 and a breakaway notch 28.Also shown are positive feedthrough groove 23 and negative feedthroughgroove 25. Those of skill in the art will appreciate grooves 23 and 25should be appropriately sized to accommodate the diameters of thefeedthrough pins. The grooves can be in the shape of, for example, a“v”, a rounded groove, or a square bottomed groove.

FIG. 2B is a top-plan view of mandrel 20 showing the mid-line of mandrel20, along line ‘m-m’. As illustrated in FIG. 2B, feedthrough grooves 23and 25 are dimensioned and configured to accept feedthrough pins 42 and44 (FIG. 1). In the embodiment illustrated in FIGS. 2A and 2B, positivefeedthrough groove 23 is placed closer to midline ‘m-m’ of mandrel 20than negative feedthrough groove 25. This is illustrated by the distance‘d’ from positive electrode groove 23 to the midline compared to thedistance from the negative electrode groove 25 to the midline ‘m-m’. Ofcourse, those of skill in the art will appreciate that the placement ofthe grooves can be equidistant from the midline. Alternatively, thenegative feedthrough groove can be closer to the mid-line, if desired,or the grooves can be placed at any convenient location of the mandrel20 as needed. However, those of skill in the art will appreciate that byhaving the feedthrough pins positioned at two different distances fromthe midline, a battery cover (not shown) can be constructed to fit overthe electrodes (not shown) in only one position. This assures that theterminals can be easily identifiable as positive and negative.

Further, as shown in FIG. 2A, removable portion 26 can be separated frompositive portion 22 and negative portion 24 by breakaway notch 28.Breakaway notch 28 can be deep enough such that mandrel 20 can be brokenalong the notch 28. This results in individual positive and negativeportions 22 and 24 of mandrel 20. In some embodiments breakaway notch 28is made in the mandrel 20 using electrical discharge machining (EDM).However, those of skill in the art will appreciate that breakaway notch28 can be formed in the mandrel using various other techniques includingmachining, laser cutting, electrochemical machining (ECM), water jetcutting, milling etc. Also illustrated in FIG. 2A is an orientationnotch 29 shown as a foot-type aperture on the midline of mandrel 20. Inthe embodiment shown, the “foot” points toward negative portion 24 ofmandrel 20. Those of skill in the art will realize that such orientationguides are not necessary for mandrel 20 to function nor do they have topoint towards the negative portion of the mandrel. However, such guidesare helpful if consistently used.

FIG. 3 shows another embodiment of an interconnect joint for anelectrode assembly 16 according to the invention. In this embodiment,grooves for positive and negative feedthrough pins 42 and 44 are onopposite faces of mandrel 20. FIG. 3 also illustrates the conductiveconnection between mandrel 20, positive and negative feedthrough pins 42and 44 and positive and negative electrodes 30 and 32. In the embodimentshown, positive and negative electrodes 30 and 32 are interposed betweenpositive and negative feedthrough pins 42 and 44 in grooves 23 and 25 onpositive and negative portions 22 and 24 of mandrel 20 respectively.When electrodes 30 and/or 32 are fixed in grooves 23 and/or 25 (notvisible) by feedthrough pins 42 and/or 44 as shown a direct electricconnection is established between feedthrough pins 42 and 44 andelectrodes 30 and 32. In some embodiments, the connection can be securedby welding both feedthrough pins 42 and 44 and electrodes 30 and 32 intothe grooves. Those of skill in the art will appreciate that when adirect connection between the electrodes 30 and 32 with feedthrough pins42 and 44 is used, as shown in FIG. 3, grooves 23 and 25 (and electrodes30 and 32) will need to be on opposite faces of mandrel 20 in order forseparator 51 to be interposed between the electrodes when the electrodesa 30/32 are wrapped around mandrel 20 to form jelly roll assembly 16.

Those of skill in the art will appreciate that when the electrodes canbe conductively connected directly to the feedthrough pins, the mandreldoes not need to be conductive to establish the conductive interconnectjoint. Therefore, in those embodiments of the invention where themandrel does not need to be electrically conductive to complete theinterconnect joint, the mandrel can be made from a non-electricallyconductive material. Suitable electrically non-conductive materials caninclude polymers including polypropylene, polyethylene, andpoly(ethylene-co-tetrafluoroethylene) (ETFE). Advantageously, theseparator(s) can be heat sealed to the mandrel when the mandrel isprepared from a non-electrically conductive material. For example, anend of the separator can be attached to a portion of the mandrel viaheat sealing.

FIG. 4 is a schematic diagram illustrating mandrel 20 with electrodes 30and 32 conductively connected to positive and negative portions 22 and24. Electrodes 30 and 32 can be attached to opposite faces of mandrel20.

Positive electrode 30 can be coated with a positive active material 302.As illustrated, positive electrode 30 has a proximal end 304 that is notcoated with active material. Proximal end 304 can be attached at by an86, such as by an ultrasonic weld, to positive portion 22 of mandrel 20.Similarly, negative electrode 32 can be coated with a negative activematerial 320. Proximal end 322 of negative electrode 21 is not coatedwith active material and facilitates attachment (not shown) to thenegative portion 24 of mandrel 20. Electrodes 30 and 32 can be attachedto the mandrel by welding such as, for example, laser welding,ultrasonic welding or resistance welding. In one embodiment, acombination of two or more welds can be included at the electrode andmandrel interface to effect attachment.

Those of skill in the art will appreciate that positive active material302 can be any of those materials used as such in electrode technology.For example, positive active material 302 can be lithium cobalt oxide(rechargeable), carbon monofluoride (CF_(x)), silver vanadium oxide(primary), or combinations thereof. Similarly, negative active material320 can be any appropriate negative active material used in electrodetechnology. Exemplary materials include lithium titanate, artificialgraphite powder (MCMB), lithium, or combinations thereof.

Both positive 30 and negative electrodes 32 can be coated on one side orboth sides of the electrode to provide an electron flow suitable togenerate a current. However, those of skill in the art will appreciatethat coating of the electrodes on both sides with active material allowsfor more efficient use of the two sides of the electrodes, resulting inincreased energy and power in contrast to a single side coatedelectrode. It should be understood that the proximal and/or distal endsof the electrodes do not need to be coated on one or both sides. Itshould be appreciated that any suitable combination of coatings andcoated portions of the electrode(s) is within the scope of the inventionand is not limiting.

FIG. 5 illustrates electrodes 30 and 32 connected to mandrel 20, asshown in FIG. 4, with positive and negative feedthrough pins 42 and 44placed in grooves 23 and 25 and secured in place. Feed through pins 42and 44 and their respective electrodes 30 and 32 can be conductivelyconnected to mandrel 20 by welding such as, for example, ultrasonicwelding and/or laser welding. In the embodiment illustrated in FIG. 5,electrodes 30 and 32 are secured to mandrel 20 using ultrasonic welding.

Alternatively, in other embodiments, a direct conductive connectionbetween the electrode and the feedthrough pin is made by attachingeither or both positive electrode 30 and negative electrode 32 ingrooves 23 and 25 underneath feedthrough pins 42 and 44 respectivelyprior to fixing feedthrough pins 42 and 44 in grooves 23 and 25. Asdiscussed for FIG. 3, when electrodes 30 and/or 32 are fixed in grooves23 and/or 25 by feedthrough pins 42 and/or 44 a direct electricconnection is established between feedthrough pins 42 and 44 andelectrodes 30 and 32.

FIG. 5 also illustrates feedthrough pins 42 and 44 extending throughinsulator 70 and battery cover 72 and used as battery terminals 80 and82. Also shown are ferrules 84 which are welded to battery cover 72 tostabilize the terminals and isolate them from battery cover 72. A glassseal or sleeve (not shown) can be placed over the feedthrough pin priorto the placement of ferrule 84 to provide a seal between the feedthroughpin and the battery cover and insulating ferrule 84 from the feedthroughpin.

Suitable materials for ferrule construction can be titanium, vanadium,stainless steel and their alloys.

Insulator 70 can be made of any insulating material such as, forexample, polyethylene, polypropylene, polyethylene terephthalate,polyimide, ethylene/tetrafluoroethylene copolymer (ETFE). In one aspect,the insulating material can be a non-conductive film such as, forexample, DuPont Kapton® polyimide film.

As discussed above, in those embodiments where feedthrough pins 42 and44 and electrodes 30 and 32 are directly connected to each other infeedthrough grooves 23 and 25 a direct electrical connection between theelectrodes and the feedthrough pins is established. Therefore, mandrel20 need not be electrically conductive to complete the interconnectjoint. This is because direct connection of the electrodes to thefeedthrough pins provides an electrical conduction between theelectrodes, the feedthrough pins and battery terminals. Of course, thoseof skill in the art will appreciate that when electrodes 30, 32 aresecured directly to mandrel 20, mandrel 20 must be electricallyconductive.

Those of skill in the art can appreciate that under the above describedconditions the battery case will be neutral. However, in otherembodiments, a stud pin (not shown) can be welded to the battery coverconcentric with groove 23 or 25 in which one of feedthrough pins 42 or44 would be positioned. Thus, in this embodiment, the case will be ateither a negative potential or a positive potential depending at whichposition the stud pin is secured.

FIG. 6 illustrates an electrode assembly as shown in FIG. 5 but viewedfrom the opposite face. In this embodiment, the electrode assembly has afirst separator 50 and a second separator 52 attached to mandrel 20. Asshown, first separator 50 and second separator 52 can be attached so asto be opposed to positive electrode 30 and negative electrode 32respectively. When wound, separators 50 and 52 isolate positive andnegative electrodes 30 and 32 from each other (shown in FIG. 7A). Theseparators can be attached to the mandrel 20 using any effective method.For example, the separators can be connected by adhesive or tape 54 thatadheres the separator to the mandrel. Tape material 54 can be apolypropylene, polyethylene, polyester, or nylon resin. Adhesivesinclude, for example, polyvinylidenefluoride (PVDF), co-polymers ofpolyhexafluoropropylene-polyvinylidenefluoride, poly(vinylacetate),polyvinylalcohol, polyethylene oxide, polyvinylpyrolidone, alkylatedpolyethylene oxide, polyvinyl ether, poly(methylmethacrylate),poly(ethylacrylate), polytetrafluoroethylene, polyvinylchloride,polyacrylonitrile, polyvinylpyridine, styrene-butadiene rubber, siliconand mixtures thereof.

FIG. 6 also shows that, as with the single separator 51 used in theembodiments shown in FIGS. 1 and 3, separators 50 and 52 are wider thanelectrodes 30 and 32 by a distance ‘m’. Those of skill in the art willappreciate that, during the process of winding the electrode assembly,some telescoping of electrodes 30 and 32 may occur. Use of separators 50and 52 that are wider than electrodes 30 and 32 helps to ensure that theelectrodes do not contact each other in the jelly roll.

FIGS. 7A-7D are schematic, top-plan views of four separate embodimentsof coiled jelly roll assemblies providing an interconnect jointaccording to the invention. FIGS. 7A and 7B are schematic diagrams ofjelly roll assemblies incorporating an interconnect joint using twodiscrete separators while FIGS. 7C and 7D are schematic diagrams ofjelly roll assemblies with interconnect joints using a single separator.

FIG. 7A shows mandrel 20 having positive and negative feedthrough pins42 and 44 on the same face with electrodes 30 and 32 connected onopposite faces of mandrel 20. Uncoated portions 304 and 322 ofelectrodes 30 and 32 can be connected to positive 22 and negative 24portions of mandrel 20 such as by welding as discussed for FIG. 5,above. Two separators 50 and 52 can be used to separate electrodes 30and 32.

FIG. 7B provides an embodiment of the invention where positive andnegative feedthrough pins 42 and 44 are on opposite faces of themandrel. In this embodiment, uncoated portions 304 and 322 of positiveand negative electrodes 30 and 32 are conductively connected tofeedthrough pins 42 and 44 by being positioned in feedthrough grooves 23and 25 behind feedthrough pins 42 and 44 making separate welding ofelectrodes 30 and 32 unnecessary. However, those of skill in the artwill appreciate that in those embodiments of mandrel 20 wherefeedthrough pins 42 and 44 are located on opposite faces of mandrel 20,electrodes 30 32 need not be secured behind feedthrough pins 42 and 44but may be secured directly to mandrel 20 such as, for example, bywelding. In the embodiment shown in FIG. 7B, two separators, 50 and 52,are shown in FIG. 7B.

Once the components of the electrode assembly 16 are assembled, mandrel20 can be rotated to wind electrodes 30 and 32 and separators 50 and 52around mandrel 20 to create the jelly roll electrode assembly 16 asshown in FIGS. 7A and 7B. FIGS. 7A and 7B also illustrate mandrel 20integrated into the center of the jelly roll electrode assembly 16 andseparators 50 and 52 wound between the positive and negative electrodes30 and 32 respectively.

FIGS. 7C and 7D illustrate separator 51 woven between positive andnegative portions 22 and 24 of mandrel 20 to insulate positive 30 andnegative 32 electrodes. FIG. 7C shows one embodiment of the interconnectjoint wherein positive and negative feedthrough pins 42 and 44 can be onthe same face of the mandrel 20. Uncoated portions 304 and 322 can beconductively connected to opposite faces of the mandrel 20, such as bywelding as discussed for FIG. 5, separator 51 passes through passage ‘p’(FIG. 3) of mandrel 20. FIG. 7D shows the interconnect joint wherepositive and negative feedthrough pins 42 and 44 can be on differentfaces of the mandrel 20. Uncoated portions 304 and 322 can beconductively connected to feedthrough pins 42 and 44 by positioning themin feedthrough grooves 23 and 25 behind feedthrough pins 42 and 44creating a direct electrical connection between feedthrough pins 42 and44 and electrodes 3 and 32 as previously discussed for FIG. 3.

As illustrated in FIGS. 7C and 7D, once the components of electrodeassembly 16 are assembled, mandrel 20 can be rotated to wind theelectrodes 30 and 32 and the single interwoven separator 51 around themandrel to create the jelly roll electrode assembly 16. FIGS. 7C and 7Dalso illustrate mandrel 20 integrated into the center of the jelly rollelectrode assembly 16 with separator 51 wound between the positive andnegative electrodes 30 and 32 respectively.

Those of skill in the art will appreciate that, by positioning a singleseparator 51 through passage “p”, the tension of the jelly rollmaintains the separator 51 in place. The jelly roll can be wound with adesired tension without risk of the separator becoming dislodged fromits position. In addition, those of skill in the art will furtherappreciate that, by use of the interconnect joint, whether a singleseparator is used or two different separators are used, there is no needfor the placement of extraneous tabs to act as electrode terminals. Theinterconnect joint results in the ends of the feedthrough pins 42 and 44being usable as positive and negative battery terminals 80 and 82.Therefore, extraneous tabs are not present that could damage the coiledjelly roll.

Rotating the mandrel to coil the jelly roll assembly can be accomplishedby using the removable portion 26. Rotating the mandrel to wind or coilthe jelly roll assembly can be performed manually. Alternatively, theprocess can be automated. For example, the removable portion 26 ofmandrel 20 can be attached to a ligature or other holding mechanism (notshown) which can be turned by a motor. The mandrel 20 can be rotated andthe process of coiling the jelly roll assembly 16 can be automated. Oncewound, those of skill in the art will appreciate that any suitable meanscan be used to keep the electrodes in place once rolled. For example,simple insulating tape can be used such as, for example, Teflon, orpolyimide tape such as, for example, DuPont Kapton®.

FIG. 8A shows the electrode assembly in battery case 64 before removableportion 26 is detached. As illustrated, battery case 64 is dimensionedso as to approximate the size of the mandrel without removable portion26. As shown in FIG. 8B, separation of the removable portion results inindividual positive portion 22 and negative portion 24 of mandrel 20integrated into the jelly roll assembly 16 and battery 10. Jelly rollassembly 16 fits within battery case 64 as illustrated in FIG. 8B.Because positive portion 22 and negative portion 24 are not removed fromthe electrode assembly 16, telescoping of the jelly roll assembly due totheir removal can be minimized or eliminated. Therefore, the jelly rollcan be wound or coiled to a tension desired to accommodate the batteryrather than coiling the jelly roll to a tension that allows the mandrelto be removed from the coil. Thus, the instant invention provides a lessbulky electrode assembly and, consequently, can be used to provide asmaller battery.

FIG. 9 illustrates a mandrel 200 according to the invention. Mandrel 200includes a positive portion 220 and a negative portion 240. Both thepositive portion 220 and the negative portion 240 include removableportions 260 a and 260 b, respectively. Positive portion 220 furtherincludes a positive feedthrough groove 230 while the negative portionincludes a negative feedthrough groove 250. As illustrated in FIG. 8, abreakaway notch 280 a and 280 b delineates the removable portion 260 aand 260 b from positive portion 220 and negative portion 240 of mandrel200. Orientation notches 290 a and 290 b can be provided in removableportion 260 a and 260 b, respectively, of positive portion 220 andnegative portion 240 of mandrel 200.

It should be understood that positive and negative electrodes (notshown) and feedthrough pins (not shown) can be attached to the positiveand negative portions 200 and 240 of mandrel 200 as previously describedherein. Additionally, it should be understood that feedthrough grooves230 and 250 can be positioned on opposite sides of mandrel 200.

Two separators (not shown) can be attached to positive and negativeportions 220 and 240 of mandrel 200 also as previously described.Alternatively, a single separator can be passed through passage “p” alsoas previously described to afford an electrode assembly.

During assembly, positive portion 220 and negative portion 240 can beheld in place, for example, by a vice and grip winding ligature (notshown) connected to the removable portions 260 a and 260 b. As with themandrel illustrated in FIG. 7B, once the jelly roll is coiled, theremovable portions can be detached. Those of skill in the art willappreciate that the mandrel shown in FIG. 8 allows each positive portion220 and negative portion 240 to be fabricated from different materialsas needed, thereby optimizing the battery and battery chemistry for adesired use.

FIGS. 10A and 10B illustrate another mandrel 300 according to theinvention. FIG. 10A is a side-plan view showing a mandrel 300 withgrooves 340 and 342 designed and configured for securing a stud pin (notshown) to the mandrel 300. Mandrel 300 also includes grooves 323 and 325designed and configured to accept positive and negative feedthrough pins(not shown). Electrodes 30 and 32 (not shown) can be secured to mandrel300 by stud pins (as shown in FIG. 12). For example, electrodes 30 and32 can be placed into grooves 340 and 342. A stud pin can then be placedover the electrode and secured into the groove to effect attachmentbetween positive portion 322 and negative portion 324 of mandrel 300.Stud pins can be made of any conductive or non-conductive material. Asillustrated in FIGS. 10A and 10B, stud pin grooves 340 and 342 can belocated on opposite faces of the mandrel. As with mandrel 20,illustrated in FIG. 2, mandrel 300 includes a positive portion 322, anegative portion 324 and a removable portion 326. Positive and negativeportions 322 and 324 are adjacent to breakaway notch 328. Mandrel 300also has positive and negative feedthrough grooves 323 and 325dimensioned and configured to accept positive and negative feedthroughpins (not shown). In this embodiment, the grooves 323 and 325 are onopposite faces of the mandrel.

Positive and negative electrodes (not shown) and feedthrough pins (notshown) can be attached to the positive and negative portions 322 and 324of mandrel 300 as previously described herein. Two separators (also notshown) can be attached to positive and negative portions 322 and 324 ofmandrel 300 also as previously described. Alternatively, a singleseparator can be passed through passage “p” also as previously describedto afford an electrode assembly.

FIGS. 11A and 11B illustrate another mandrel according to the invention.Mandrel 400 includes a positive portion 422, a negative portion 424 anda removable portion 426. Positive and negative portions 422 and 424 areadjacent to breakaway notch 428. As with mandrel 300, illustrated inFIGS. 10A and 10B, mandrel 400 is designed and configured for theelectrodes (not shown) to be attached to mandrel 400 using a stud pin(444 shown in FIG. 12). As shown in FIG. 11A, mandrel 400 provides forpositive stud pin groove 440, positive feedthrough pin groove 423 andnegative feed through pin groove 425 to be on the same face of mandrel400 while negative stud pin groove 442 is on the opposite face of themandrel.

As with FIGS. 9, 10A and 10B, positive and negative electrodes (notshown) and feedthrough pins (not shown) can be attached to positive andnegative portions 422 and 424 of mandrel 400 as previously describedherein. Two separators (also not shown) can be attached to positive andnegative portions 422 and 424 of mandrel 400 also as previouslydescribed. Alternatively, a single separator can be passed throughpassage “p” also as previously described to afford an electrodeassembly.

FIG. 12 is a side-plan view of mandrel 400 (FIGS. 10A and 10B) partiallyassembled into an electrode assembly. FIG. 12 shows positive electrode30 anchored underneath stud pin 444 in groove 440. Both electrode 30 andstud pin 444 can be connected to mandrel 400 together in groove 440 toprovide conductive attachment of electrode 30 to mandrel 400 and throughmandrel 400 to feedthrough pin 42 to create a conductive interconnectjoint. Positive feedthrough pin 42 and negative feedthrough pin 44 areon the same face of the mandrel while negative electrode 32 can beconnected to mandrel 400 using a stud pin (not shown) on the oppositeface of the mandrel 400.

Two separators (also not shown) can be attached to positive and negativeportions 422 and 424 of mandrel 400 also as previously described.Alternatively, a single separator can be passed through passage “p” alsoas previously described to afford an electrode assembly.

In an alternative embodiment, the mandrel can be made from anon-electrically conductive material. Such electrically non-conductivematerials can include polymers including polypropylene, polyethylene,and poly(ethylene-co-tetrafluoroethylene) (ETFE). The mandrel canresemble mandrel 20 as illustrated in FIG. 3, such that there is adirect electrical connection between the electrodes and the feedthroughpins positioned in the mandrel.

FIG. 13 is a schematic, cross-sectional representation of a throughpenetration weld of positive feedthrough pin 42 to one embodiment ofmandrel 20. Those of skill in the art will appreciate that, in securingpins 42, 44 to mandrel 20, it is important to make the weld as robust aspossible without damaging the integrity of mandrel 20 or pins 42, 44. Tothis end, the inventors have identified several advantageous strategies.As shown in FIG. 13, according to one embodiment, a laser beam 464 isused to make a through penetration weld of mandrel 20 to feedthrough pin42 by making the laser incident on the face opposite of that from whichgroove 23 and pin 42 are located essentially welding the much largermandrel 20 to feedthrough pins 42, 44 instead of pins 42, 44 to mandrel20 insuring integrity of the weld and pins.

Therefore, in one exemplary embodiment, laser beam 464 travels in thedirection of arrow 466 from a distal end of pin 42 (or 44) towardterminal 80 (or 82). In this embodiment laser beam 464 tracks fromon-center of feedthrough pin 42 to off-center of feedthrough pin 42.This path is illustrated by the wedge-shaped weld penetration profile468 which also represents the decreasing energy applied to pin 42 aslaser 464 travels toward terminal 80 in direction of arrow 466. However,in various other embodiments, it is within the scope of the inventionthat the beam 464 maintains an on-center path while the power applied topin 42/weld decreases as laser 464 travel along path 466 toward terminal80.

Those of skill in the art will appreciate that power penetration profile468 illustrates decreasing power of the laser from its initial point ofincidence at the distal end of pin 42 as it travels along pin 42 towardterminal 80. The decrease in power penetration ensures that pins 42 and44 are securely welded to mandrel 20 by the higher power at initialincidence and the integrity of pins 42 and 44 remains unaffected at theterminal end of laser path 466.

Through penetration welding of feedthrough pins 42, 44 from the oppositeface of mandrel 20 provides certain benefits. First, it allows mandrel20 to be welded to the feedthrough pins 42 and 44 instead of welding thefeedthrough pins to mandrel 20. Those of skill in the art willappreciate that mandrel 20 being much larger and with a greater massthan feedthrough pins 42, 44 provides greater material for the weld thanwould welding of the feedthrough pins to the mandrel. Second, weldingthe mandrel 20 from the opposite face than grooves 23, 25 are locatedallows molten mandrel material to fill grooves 23, 25, aroundfeedthrough pins 42, 44 with molten mandrel material, increasing thestrength of the weld and eliminating any residual “air gap” between thefeedthrough pins 42, 44 and the grooves 23, 25. Therefore, the strengthof the weld is more robust than it would be if the smaller feedthroughpin was melted to form the weld.

As discussed below, the theoretical focal spot of the laser used in theembodiment illustrated in FIGS. 13-15 is approximately 0.016 in. (0.406mm). In addition, FIG. 15 is micrograph showing a single incidence spotfrom a pulsed, through penetration weld. As shown, the side of themandrel on which the laser is incident leaves a spot having a diameterof approximately 1.0 mm while on the opposite side of the mandrel, theweld spot is approximately 0.25 mm. As seen schematically in FIGS. 13and 14 and shown in the micrograph, FIG. 15, while the through weldmelts completely through the mandrel, the size of the weld spot, inrelation to the size of the mandrel is small, in relation to the size ofthe mandrel, the weld spot is small and does not adversely affect theintegrity of the mandrel. Of course, those of skill in the art willappreciate that the size of the focal spot and/or the power used andduration of pulse will change for different lasers used.

FIG. 14 is a side elevation view of one embodiment of mandrel 20according to the invention. In this embodiment, both an ultrasonic weld306 and a through penetration laser weld 462 create a hybrid weld306/462 used to attach one or both electrodes 30/32 to mandrel 20. Inthe embodiment of electrode assembly 16 illustrated, feedthrough grooves23, 25 and feedthrough pins 42, 44 are fixed to the same face of mandrel20, as is the positive electrode 30. Negative electrode 32 is fixed tothe opposite face of mandrel 20. In the embodiment shown, threeultrasonic welds 306 are used to attach each of the electrodes tomandrel 20 and each ultrasonic weld is reinforced with a throughpenetration laser weld 462 having a laser incidence point 460 on theopposite face of mandrel 20 than the electrodes 30, 32 are fixed on.However, in some embodiments, only one of the ultrasonic welds 306 isreinforced with a through penetration laser weld 462, as illustrated inFIG. 13.

Similarly, it is within the scope of the invention to reinforce only twoof the ultrasonic welds with a through penetration laser weld. Inaddition, in some embodiments, only one of the electrodes is reinforcedwith a through penetration laser weld. For example, the positiveelectrode is more prone to corrosion from the electrolyte solutioncontained within the battery case (not shown) upon completion of thebattery. Therefore, reinforcement of the negative electrode with athrough penetration weld may not be required. However, in some instancesa single through penetration weld of the positive electrode may besufficient to overcome any concerns regarding the security of thepositive electrode.

In various embodiments, ultrasonic weld 306 is made by the highfrequency vibration of weld a weld plate (or horn and opposing anvil)(not shown) having a plurality of knurls that vibrate at high frequencyagainst the electrode thereby welding it to the mandrel. In theseembodiments, the imprint of the knurls into the electrode 30, 32 and theunderlying mandrel 20, results in an increase in the surface area of theelectrode 30, 32 in contact with the mandrel by a factor commensuratewith the deformation of the knurls when compared to the flat electrodefoil 304. In some embodiments, the frequency of vibration of theultrasonic welding head may be from about 20 kHz to about 70 kHz. Inother embodiments the vibration frequency may be about 40 kHz.Consequent through penetration by laser beam 464 of mandrel 20 at thelocation of ultrasonic weld 306 results in molten mandrel materialflowing into the area between the horns of the knurls reinforcingattachment of the electrodes 30, 32 to the mandrel. In some embodimentsthe laser may be a solid state laser, such as, for example, a Trumpf NdYAG-Laser HL 3006D. When solid state lasers are used the power can rangefrom about 600 W to about 630 W peak with a pulse width of aboutapproximately 17-17.5 mm. In these embodiments the energy use is aboutapproximately 10-11.5 joules with a theoretical focus spot ofapproximately 0.016 in (0.406 mm). Of course, those of skill in the artwill appreciate that use of different lasers may require differentparameters to achieve through penetration of mandrel 20 withoutdestruction of the underlying electrode foil 304.

Those of skill in the art will appreciate that while three discreteultrasonic welds 306 are illustrated for each electrode 30/32, in someembodiments, a single ultrasonic weld may be used such as for exampleultrasonic weld 86 shown in FIG. 4. When a single weld is used one ormore through penetration laser welds 462 may also be used. In addition,in the embodiment illustrated in FIG. 14, the ultrasonic welding headhas a horn density of 3×39 knurl points. To make the weld the weldinghead can generally vibrate between about approximately 20 kHz to aboutapproximately 60 kHz.

FIG. 15 is an electron micrograph of a cross section of mandrel 20showing a through penetration weld of mandrel 20 from laser incidence460 to laser weld 462 and impacting electrode foil 306. Knurls 470 madeby made ultrasonic weld are visible in this view. Bar is 1⁻² inch (0.25mm).

The following paragraphs enumerated consecutively from 1 through 35provide for various aspects of the present invention. In one embodiment,in a first paragraph (1), the present invention provides:

1. An electrode assembly comprising:

-   -   a mandrel having a first face and a second face, comprising a        positive portion, a negative portion and one or more removable        portions;    -   a positive electrode;    -   a negative electrode;    -   a positive feedthrough pin; and    -   a negative feedthrough pin;        wherein the positive portion and the negative portion are        connected by one or more removable portions;        wherein the positive feedthrough pin is connected to the        positive portion and the negative feedthrough pin is connected        to the negative portion;        wherein the positive electrode is attached to the positive        portion and the negative electrode is attached to the negative        portion;        wherein one or both electrodes are connected to the mandrel by        one or more ultrasonic welds from the same face of the mandrel        to which the one or both electrodes are attached; and        wherein one or both electrodes are connected to the mandrel by        one or more laser welds from the opposite face of the mandrel        from which the one or both electrodes are attached.

2. The electrode assembly of paragraph 1, wherein the ultrasonic weldprovides one or more knurls.

3. The electrode assembly of paragraph 1 or 2, wherein the laser weld isfoimed about the one or more knurls.

4. The electrode assembly of any of paragraphs 1 through 3, wherein thepositive portion and/or the negative portion have a groove configured toaccept the feedthrough pins.

5. The electrode assembly of any of paragraphs 1 through 4, wherein thepositive and negative feedthrough pins are independently selected fromsteel, platinum, aluminum, titanium, vanadium, niobium, molybdenum,platinum-iridium, and copper and their alloys.

6. The electrode assembly of any of paragraphs 1 through 5, wherein thepositive and negative electrodes are independently selected fromaluminum, steel, silver, copper, nickel, titanium, vanadium or alloysthereof

7. The electrode assembly of any of paragraphs 1 through 6, wherein thepositive electrode is coated with a positive active material selectedfrom lithium cobalt oxide (rechargeable), carbon monofluoride (CFx),silver vanadium oxide (primary), or combinations thereof.

8. The electrode assembly of any of paragraphs 1 through 7, wherein thenegative electrode is coated with a negative active material selectedfrom lithium titanate, artificial graphite powder (MCMB), lithium orcombinations thereof

9. The electrode assembly of any of paragraphs 1 through 8, wherein themandrel is formed from an electrically conductive material selected fromstainless steel, aluminum, titanium, vanadium, nickel, copper theiralloys and combinations thereof.

10. The electrode assembly of paragraph 10, wherein the positiveelectrode, the negative electrode, or both is/are interposed in thegroove between the positive feedthrough pin or negative feedthrough pinand the mandrel.

11. The electrode assembly of any of paragraphs 1 through 10, wherein apassage is interposed between the positive and the negative portions.

12. The electrode assembly of paragraph 11, wherein a separator strip ispassed through the passage.

13. The electrode assembly of paragraph 12, wherein the electrodes andthe separator strip are wound around the mandrel.

14. The electrode assembly of any of paragraphs 1 through 13, whereinthe one or more removable portions are detached.

15. A method of preparing an electrode assembly comprising:

-   -   providing a mandrel having a first face and a second face and        comprising a positive portion and a negative portion connected        by one or more removable portions;    -   providing a positive electrode;    -   providing a negative electrode;    -   providing a positive feedthrough pin;    -   providing a negative feedthrough pin;    -   connecting the positive feedthrough pin to the positive portion        and the negative feedthrough pin to the negative portion;    -   attaching the positive electrode to a face of the positive        portion by ultrasonic welding from the same face of the mandrel        to which the electrode is attached;    -   attaching the negative electrode to a face of the negative        portion by ultrasonic welding from the same face of the mandrel        to which the electrode is attached; and    -   attaching the positive electrode, the negative electrode or both        to a face of the positive portion and/or the negative portion        respectively by laser welding from the opposite face of the        mandrel to which the electrode is attached.

16. A method of preparing an electrode assembly of paragraph 15, whereinthe ultrasonic welding provides one or more knurls.

17. A method of preparing an electrode assembly of paragraph 16, whereinthe laser welding provides molten mandrel material about the one or moreknurls.

18. The method of preparing an electrode assembly of any of paragraphs15 through 17, further comprising the step of providing a grooveconfigured to accept the positive feedthrough pin on the positiveportion on a face of the mandrel.

19. The method of preparing an electrode assembly of paragraph 18,wherein the positive feedthrough pin is conductively connected in thegroove on the positive portion.

20. The method of preparing an electrode assembly of any of paragraphs15 through 19, further comprising the step of, providing a grooveconfigured to accept the negative feedthrough pin on the negativeportion on a face of the mandrel.

21. The method of preparing an electrode assembly of paragraph 20,wherein the negative feedthrough pin is conductively connected in thegroove on the negative portion.

22. The method of preparing an electrode assembly of any of paragraphs15 through 21, wherein the positive and negative feedthrough pins areindependently selected from steel, platinum, aluminum, titanium,vanadium, niobium, molybdenum, platinum-iridium, and copper and theiralloys.

23. The method of preparing an electrode assembly of any of paragraphs15 through 22, wherein the positive and negative electrodes areindependently selected from aluminum, steel, silver, copper, nickel,titanium, vanadium, or alloys thereof

24. The method of preparing an electrode assembly of paragraph 23,wherein the positive electrode is coated with a positive active materialselected from lithium cobalt oxide (rechargeable), carbon monofluoride(CFx), silver vanadium oxide (primary), or combinations thereof.

25. The method of preparing an electrode assembly of paragraph 23,wherein the negative electrode is coated with a negative active materialselected from lithium titanate, artificial graphite powder (MCMB),lithium, or combinations thereof.

26. The method of preparing an electrode assembly of any of paragraphs15 through 25, wherein the mandrel is fanned from an electricallyconductive material selected from stainless steel, aluminum, titanium,vanadium, nickel, copper, their alloys or combinations thereof.

27. The method of preparing an electrode assembly of any of paragraphs15 through 26, wherein the positive electrode, the negative electrode,or both is/are interposed in the groove between the positive feedthroughpin or negative feedthrough pin and the mandrel.

28. The method of preparing an electrode assembly of any of paragraphs15 through 27, further including passing a separator strip through apassage between the positive and the negative portions.

29. The method of preparing an electrode assembly of paragraph 28,further including winding the electrodes and the separator strip aroundthe mandrel.

30. The method of preparing an electrode assembly of paragraph 29,wherein winding is accomplished by rotating the mandrel.

31. The method of preparing an electrode assembly of paragraph 30,further comprising the step of detaching the one or more removableportions.

32. The electrode assembly of any of paragraphs 1 through 14, whereinthe mandrel is planar.

33. The method of preparing an electrode assembly of any of paragraphs15 through 31, wherein the mandrel is planar.

34. The method of preparing an electrode assembly of any of paragraphs15 through 31 and 33, wherein either the laser welding or the ultrasonicwelding can be performed first.

35. The method of preparing an electrode assembly of paragraph 34,wherein the order of attaching the positive electrode or the negativeelectrode can be in any order.

While this invention has been described in conjunction with the variousexemplary embodiments outlined above, various alternatives,modifications, variations, improvements and/or substantial equivalents,whether known or that are or may be presently unforeseen, may becomeapparent to those having at least ordinary skill in the art.Accordingly, the exemplary embodiments according to this invention, asset forth above, are intended to be illustrative not limiting. Variouschanges may be made without departing from the spirit and scope of theinvention. Therefore, the invention is intended to embrace all known orlater-developed alternatives, modifications, variations, improvementsand/or substantial equivalents of these exemplary embodiments.

What is claimed is:
 1. An electrode assembly comprising: a mandrelhaving a first face and a second face, comprising a positive portion, anegative portion and one or more removable portions; a positiveelectrode; a negative electrode; a positive feedthrough pin; and anegative feedthrough pin; wherein the positive portion and the negativeportion are connected by one or more removable portions; wherein thepositive feedthrough pin is connected to the positive portion and thenegative feedthrough pin is connected to the negative portion; whereinthe positive electrode is attached to the positive portion and thenegative electrode is attached to the negative portion; wherein one orboth electrodes are connected to the mandrel by one or more ultrasonicwelds from the same face of the mandrel from which the one or bothelectrodes are attached; and wherein one or both electrodes areconnected to the mandrel by one or more laser welds from the oppositeface of the mandrel to which the one or both electrodes are attached. 2.The electrode assembly of claim 1, wherein the ultrasonic weld providesone or more knurls.
 3. The electrode assembly of claim 1, wherein thelaser weld is formed about the one or more knurls.
 4. The electrodeassembly of claim 1, wherein the positive portion and/or the negativeportion have a groove configured to accept the feedthrough pins.
 5. Theelectrode assembly of claim 1, wherein the positive and negativefeedthrough pins are independently selected from steel, platinum,aluminum, titanium, vanadium, niobium, molybdenum, platinum-iridium, andcopper and their alloys.
 6. The electrode assembly of claim 1, whereinthe positive and negative electrodes are independently selected fromaluminum, steel, silver, copper, nickel, titanium, vanadium or alloysthereof.
 7. The electrode assembly of claim 1, wherein the positiveelectrode is coated with a positive active material selected fromlithium cobalt oxide (rechargeable), carbon monofluoride (CFx), silvervanadium oxide (primary), or combinations thereof.
 8. The electrodeassembly of claim 1, wherein the negative electrode is coated with anegative active material selected from lithium titanate, artificialgraphite powder (MCMB), lithium or combinations thereof.
 9. Theelectrode assembly of claim 1, wherein the mandrel is formed from anelectrically conductive material selected from stainless steel,aluminum, titanium, vanadium, nickel, copper, their alloys orcombinations thereof
 10. The electrode assembly of claim 10, wherein thepositive electrode, the negative electrode, or both is/are interposed inthe groove between the positive feedthrough pin or negative feedthroughpin and the mandrel.
 11. The electrode assembly of claim 1, wherein apassage is interposed between the positive and the negative portions.12. The electrode assembly of claim 11, wherein a separator strip ispassed through the passage.
 13. The electrode assembly of claim 12,wherein the electrodes and the separator strip are wound around themandrel.
 14. The electrode assembly of claim 1, wherein the one or moreremovable portions are detached.
 15. A method of preparing an electrodeassembly comprising: providing a mandrel having a first face and asecond face and comprising a positive portion and a negative portionconnected by one or more removable portions; providing a positiveelectrode; providing a negative electrode; providing a positivefeedthrough pin; providing a negative feedthrough pin; connecting thepositive feedthrough pin to the positive portion and the negativefeedthrough pin to the negative portion; attaching the positiveelectrode to a face of the positive portion by ultrasonic welding fromthe same face of the mandrel to which the electrode is attached;attaching the negative electrode to a face of the negative portion byultrasonic welding from the same face of the mandrel to which theelectrode is attached; and attaching the positive electrode, thenegative electrode or both to a face of the positive portion and/or thenegative portion respectively by laser welding from the opposite face ofthe mandrel to which the electrode is attached.
 16. A method ofpreparing an electrode assembly of claim 15, wherein the ultrasonicwelding provides one or more knurls.
 17. A method of preparing anelectrode assembly of claim 16, wherein the laser welding providesmolten mandrel material about the one or more knurls.
 18. The method ofpreparing an electrode assembly of claim 15, further comprising the stepof providing a groove configured to accept the positive feedthrough pinon the positive portion on a face of the mandrel.
 19. The method ofpreparing an electrode assembly of claim 18, wherein the positivefeedthrough pin is conductively connected in the groove on the positiveportion.
 20. The method of preparing an electrode assembly of claim 15,further comprising the step of, providing a groove configured to acceptthe negative feedthrough pin on the negative portion on a face of themandrel.
 21. The method of preparing an electrode assembly of claim 20,wherein the negative feedthrough pin is conductively connected in thegroove on the negative portion.
 22. The method of preparing an electrodeassembly of claim 15, wherein the positive and negative feedthrough pinsare independently selected from steel, platinum, aluminum, titanium,vanadium, niobium, molybdenum, platinum-iridium, copper and alloysthereof.
 23. The method of preparing an electrode assembly of claim 15,wherein the positive and negative electrodes are independently selectedfrom aluminum, steel, silver, copper, nickel, titanium, vanadium, andalloys thereof.
 24. The method of preparing an electrode assembly ofclaim 23, wherein the positive electrode is coated with a positiveactive material selected from lithium cobalt oxide (rechargeable),carbon monofluoride (CFx), silver vanadium oxide (primary), orcombinations thereof.
 25. The method of preparing an electrode assemblyof claim 23, wherein the negative electrode is coated with a negativeactive material selected from lithium titanate, artificial graphitepowder (MCMB), lithium, or combinations thereof.
 26. The method ofpreparing an electrode assembly of claim 15, wherein the mandrel isformed from an electrically conductive material selected from stainlesssteel, aluminum, titanium, vanadium, nickel, copper, and alloys thereof.27. The method of preparing an electrode assembly of claim 15, whereinthe positive electrode, the negative electrode, or both is/areinterposed in the groove between the positive feedthrough pin ornegative feedthrough pin and the mandrel.
 28. The method of preparing anelectrode assembly of claim 15, further including passing a separatorstrip through a passage between the positive and the negative portions.29. The method of preparing an electrode assembly of claim 28, furtherincluding winding the electrodes and the separator strip around themandrel.
 30. The method of preparing an electrode assembly of claim 29,wherein winding is accomplished by rotating the mandrel.
 31. The methodof preparing an electrode assembly of claim 30, further comprising thestep of detaching the one or more removable portions.
 32. The method ofpreparing an electrode assembly of claim 15, wherein the mandrel isplanar.
 33. The method of preparing an electrode assembly of claim 15,wherein either the laser welding or the ultrasonic welding can beperformed first.
 34. The method of preparing an electrode assembly ofclaim 33, wherein the order of attaching the positive electrode or thenegative electrode can be in any order.